Answer:
d. Both A & C
Explanation:
- The velocity of the ball is a vector, whose magnitude indicates its rate of change of position, and it has a direction. In this case, the ball is moving upward, therefore the direction of motion is upward, so the direction of the velocity is upward as well.
- The acceleration of the ball is a vector, whose magnitude indicates the rate of change of the velocity. The direction of the acceleration is:
-- positive if the the magnitude of the velocity is increasing
-- negative if the magnitude of the velocity is decreasing
For a ball thrown upward, the acceleration is given by the acceleration of gravity, . This acceleration points downward, and it is constant during the entire motion. In particular, it does not change direction, as it is always directed downward. Therefore, the acceleration of the ball is downward.
So, the correct answer is
d.Both A & C
Since A and C are both true:
a.The velocity vector is directed upward.
c.The acceleration is directed downward.
Answer:
Approximately .
Explanation:
The refractive index of the air is approximately
.
Let denote the refractive index of the glass block, and let
denote the angle of refraction in the glass. Let
denote the angle at which the light enters the glass block from the air.
By Snell's Law:
.
Rearrange the Snell's Law equation to obtain:
.
Hence:
.
In other words, the angle of refraction in the glass would be approximately .